fix json emitter for empty response bodies (#178)

* fix json emitter for empty response bodies

* Update django_declarative_apis/resources/emitters.py

Co-authored-by: bgrant <[email protected]>

* pr feedback

* changelog update, version bump

---------

Co-authored-by: bgrant <[email protected]>

Author: demianbrecht

.bumpversion.cfg

@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 0.33.0
+current_version = 0.34.0
 
 [bumpversion:file:pyproject.toml]
 

CHANGELOG.md

@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # [Unreleased]
 
+# [0.34.0]
+- [PR 178](https://github.com/salesforce/django-declarative-apis/pull/178) Fix JSONEmitter for empty response bodies.
+
 # [0.33.0]
 - [PR 170](https://github.com/salesforce/django-declarative-apis/pull/170) Update publish workflow
 - [PR 173](https://github.com/salesforce/django-declarative-apis/pull/173) handle request.GET or request.POST being None + a few other improvements

django_declarative_apis/resources/emitters.py

@@ -182,20 +182,24 @@ def decode(self, data):
 
     def render(self, request):
         cb = request.GET.get("callback", None)
-        assert cb is None, "JSONP Callbacks not suppoted"
-        seria = json.dumps(
-            self.decode(self.construct()),
-            cls=DjangoJSONEncoder,
-            ensure_ascii=False,
-            indent=4,
-        )
+        assert cb is None, "JSONP Callbacks not supported"
+        seria = self.decode(self.construct())
+        if isinstance(seria, list):
+            if len(seria) == 0 or (len(seria) == 1 and len(seria[0]) == 0):
+                # the body is empty, no need to run json.dumps
+                return ""
 
         # Callback
         # TODO: do we care about JSONP?
         # if cb and is_valid_jsonp_callback_value(cb):
         #     return '%s(%s)' % (cb, seria)
 
-        return seria
+        return json.dumps(
+            seria,
+            cls=DjangoJSONEncoder,
+            ensure_ascii=False,
+            indent=4,
+        )
 
 
 Emitter.register("json", JSONEmitter, "application/json; charset=utf-8")

docs/source/conf.py

@@ -75,7 +75,7 @@
 # built documents.
 
 # The full version, including alpha/beta/rc tags.
-release = "0.33.0"  # set by bumpversion
+release = "0.34.0"  # set by bumpversion
 
 # The short X.Y version.
 version = release.rsplit(".", 1)[0]

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "django-declarative-apis"
-version = "0.33.0"  # set by bumpversion
+version = "0.34.0"  # set by bumpversion
 description = "Simple, readable, declarative APIs for Django"
 readme = "README.md"
 dependencies = [

tests/resources/test_emitters.py

@@ -109,6 +109,15 @@ def test_decode(self):
         resp = em.render(django.test.RequestFactory().get("/"))
         self.assertEqual(json.loads(resp), ["foo", "bar"])
 
+    def test_decode_empty_list(self):
+        em = emitters.JSONEmitter([""], lambda: None)
+        resp = em.render(django.test.RequestFactory().get("/"))
+        self.assertEqual(resp, "")
+
+        em = emitters.JSONEmitter([], lambda: None)
+        resp = em.render(django.test.RequestFactory().get("/"))
+        self.assertEqual(resp, "")
+
 
 class DjangoEmitterTestCase(unittest.TestCase):
     def test_render_http_response_succes(self):